ECMA 262 is a standard that defines the core features of the JavaScript language. The language that is defined by this standard is called ECMAScript. JavaScript is an implementation of ECMAScript. It runs in web browsers at the client end, while Node.js runs at the server end. ECMAScript 6 was released in June 2015. ES6 is a major update from ES5, which was released in 2009.
A complete language specifications draft of ES6 language specifications can be obtained from https://people.mozilla.org/~jorendorff/es6-draft.html.